Message 2/525 Jonathan Quick                        Oct 18, 2000 11:29:53 am
+0200

Date: Wed, 18 Oct 2000 11:29:53 +0200 (SAST)
To: evntech@jb.man.ac.uk
Subject: EVNtech: HH TOG report
Sender: owner-evntech@jb.man.ac.uk
Precedence: bulk

Unaffiliated Station:  Hartebeesthoek (HartRAO)
Author              :  Jonathan Quick
Date                :  Oct 18, 2000


Personnel Changes
-----------------
None.


Brief Report of Last EVN Session
--------------------------------
A failure of the 5V Sync power supply in the Mark IV data acquisition rack
during the session forced us to use a temporary switched mode PC power
supply kludge.  This proved to be marginal and one VC (VC4) reacted to
the slight drop in supply voltage and gave problems during EP037B.  The
faulty supply has since been repaired and re-installed.  The problem in
VC4 appears to have been due to a dirty connector contact triggered by the
module swapping that occured during diagnosis of the power supply fault.

Although the 6GHz receiver is in the process of being upgraded to dual
polarisation, this was not ready in time for the session and has since
been further delayed by the failure of post amplifiers during testing.


Problems Encountered Since Last TOG Meeting
-------------------------------------------
The PCFS computer hung completely during an experiment to such a degree
that it did not respond even to  a network "ping".  Cycling the power
reset the computer and it behaved normally thereafter.  There was no
evidence of any problem in either system or FS logfiles.


Changes/Upgrades Made to Hardware/Software
------------------------------------------
o Current FS version: 9.4.13.
o Antenna control computer now handles sources beyond northern limits
  sensibly.
o Switching between receivers is fully computer controllable using a
  station LO command except for L-band which needs manual intervention.

o All standard VLBI receivers now dual polarisation ( L, S, C and X band.)
  6GHz spectral line receiver will be dual polarisation shortly.
o Installed NEW Mark IV Decoder !!


Outstanding Concerns/Problems
-----------------------------
o Local reproduce problems continue.  A vacuum shift problem with the Mark
  IV recorder still has to be resolved.  
o Our headstack is still under investigation at Haystack to resolve a 8"
  vacuum flying problem.  A second-hand headstack has been installed on the
  recorder in the interim.